Hodgkin's disease (HD) risk is increased in family members of patients. If proband-reported family histories of HD were known to be accurate, efficient studies of HD family association, inheritance patterns and susceptibility genes could be conducted without additional patient contact, using new statistical methods and stored tumor tissues. However, no data exist on the validity of self-reported family history of HD or other lymphoma, with which HD is often confused. In a prior population-based, case- control study of HD for which we interviewed 645 women and enumerated their 1st-, 2nd-, and 3rd-degree blood relatives, we found a significant excess of familial HD, the first such population-based finding. The proposed R03 study will validate the positive family histories of HD and other lymphoma provided by 50 probands, against medical record and/or death certificate reports, to explore the utility of proband-reported family histories for future genetic studies of familial HD, and to provide the first population-based description of validated familial HD and associated risk in women. The study will: 1) interview the 33 HD case and 17 population-control probands by phone for contact information on the 58 blood relatives they had reported as having HD or other lymphoma; 2) contact the 58 relatives or their next-of-kin by phone to obtain their cancer history and access to pathology reports and discharge summaries, or, as needed, death certificates, for diagnostic review; 3) obtain the diagnostic documents, and review and classify diagnoses per cancer-registry standards; 4) compare reported and documented diagnoses to calculate validity of proband-reported family history of HD and of other lymphoma, for 1st-, 2nd-, and selected 3rd-degree relatives; 5) describe validated familial HD and associated risk in the original population-based HD case series. Study strengths are: 1) inclusion of population-based, proband-derived histories for 1st-, 2nd-, and selected 3rd- relatives, so that findings are both generalizable and extend beyond 1st-degree relatives; 2) validation of HD and of other lymphomas, both reported in high-risk families but often hard to differentiate; 3) use of a documentation hierarchy: medical record, death certificate, and relative's self-report. Establishing validity of proband-reported lymphomas will help us determine the usefulness of high-risk pedigrees reported by HD probands, who could be identified for this purpose efficiently and in adequate numbers by cancer-registry screening, and will expand the literature on cancer-history validation to include HD. Study results also have implications to the utility of self- reported family history of lymphoma for counseling lymphoma family members about disease risk.